I really believe the only possible solution (other than just giving up and adding a CD player to my car) is the watermark thing.

Hmm, thinking about the watermark issue...

The whole point of watermarking, whether it be for audio files, images, movies, whatever, is that the watermark is supposed to tolerate modifications. For instance, the whole SDMI-hacking thing was all about this. The idea is that you could make a copy of a piece of music or an image, mess around with it (data compress it, alter its volume, etc.) and still have the watermark be readable.

If the point of having IASCA-certified digital music tracks is to verify that the files were not tampered, then watermarking is precisely the opposite technology to use.

Unless there's some sort of watermarking technology I don't know about that's been deliberately designed to detect tampering, but it seems to me that such a technology would have a different name than "watermark" since its purposes are different.

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Tony Fabris